Packages with three side gusset are available on the market today for packing liquids and solids and different manufacturing methods are used for the same. These kinds of bags with three side gussets are known in the numerous embodiments, which depend on the use, to which they are to be put. One type of plastic bag forming machine and method of operation is disclosed in U.S. Pat. No. 4,929,224 to Hanson et al., which uses closed sleeve plastic material with inwardly gusseted sides as a raw starting material. Another method of making flat-bottomed plastic bags is disclosed in U.S. Pat. No. 5,102,384.
U.S. Pat. No. 6,056,681 provides a method and apparatus for forming flat-bottomed plastic bags which gives more consistent and precise results than are obtainable using pre-gusseted tubing.
The plastic bag is advantageous in that the first and second side gusset portions can be unfolded between the first and second side edges respectively to obtain a large capacity. The bottom gusset portion and the first and second auxiliary gusset portions can also be unfolded between the bottom edges to constitute a rectangular bottom. The plastic bag can therefore stably stand on a table. However, it has been heretofore difficult to successively make the plastic bags. Further, there are several method of manufacturing the packages with three side gussets are also disclosed in various patent applications and patents.
U.S. Pat. No. 6,561,963 and EP 1106339 disclose a new and improved apparatus for successively making plastic bags where every bag is completed with first and second side gusset portions and then a bottom gusset portion. U.S. patent application Ser. No. 10/052,267 which is continuation application with respect to said U.S. Pat. No. 6,561,963 and matured as U.S. Pat. No. 6,692,148 provides plastic bag making apparatus.
U.S. Pat. No. 6,425,847 provides a method for producing a packing material from plastic film or a similar weldable material in the form of a bag or sack with side folds of the initially given type.
In our co-pending application number 582/MUM/2004, we have described a reclosable flexible package with a slider zipper assembly and three-side gusset having a handle and a method of manufacturing the same.
However the methods used in the above-mentioned documents are very complicated. Further, the methods used in the above-mentioned patent applications/patents increase the rejection rate in the manufacturing of package. Additionally, packages produced by the methods and apparatus disclosed in the documents may not have good dimensional accuracy.